Preparation of complex diaryl guanidine metal salt addition compounds



Patented Oct. 14, 1941 PREP RATIONOF COMPLEX DIARYL GUAN- IDINE 'META L' ,SALTf' ADDITION COM- POUNDS Arnold It. Davis, Old Greenwich, Conn., assign- ,or to America'nfCyanamid Company, New York, N. Y.,' acorporaticn ofMaine No Drawing; Application August '3, 1940,,

, serial No. 351,155

77 Claims. (c1. zeal-142 9) This invention relates to amethod of preparing complex diaryl guanidine addition products of the type described in my copending application, Serial No. 351,156, filed ,concurfentlyherewith. I have found that the complex addition products obtainable by reacting diaryl guanidines with zinc chloride and aluminum chloride AlCl3.6H2O described in that application can be prepared in a form requiring little or no further purification by a solvent process, and this process constitutes the subject matter of the present application. My present process,'a s applied to the preparation of complex addition products of diaryl guanidines with zinc chloride and aluminum chloride, is essentially the same as the process described in my copending application, Serial No. 223,206, filed August 5, 1938, and the present application is a continuation-in-part of that case.

I have found that complex diaryl guanidine addition products of the formula in which ArG is a diaryl guanidine such as diphenyl guanidine, di-o-tolyl guanidine, phenylo-tolyl guanidine and the like can be prepared by dissolving the metal chloride in alcohol, such as methyl or ethyl alcohol, and reacting the guanidine therewith, either as such or in the form of an alcoholic solution. The complex addition product is formed at elevated temperatures by heating the alcoholic solution to its boiling point, preferably with refluxing for /2 to 1 hour, and the excess alcohol is then preferably removed by distillation or evaporation.

As is described in my copending application above referred to, the activating properties of my new complex addition products for rubber accelerators are greatly improved when the complex product is obtained in the glassy, resin-like amorphous state, and the present process is especially well adapted for obtaining the products in this form. Thus, for example, the alcoholic solution of the product may be evaporated to complete dryness and the heating continued until the resulting solid product is fused at a temperature slightly above its melting point, but below the temperature of decomposition of the diaryl guanidine which it contains. Alternately, only a part of the alcohol may be evaporated and certain of the complex addition products obtained by crystallization, and these products may then be fused as before. In both cases, however, it

is an advantage of my invention that substantially quantitative yields obtained.

The invention willbe illustrated in greater detail by the following specific examples, parts being by weight. It 'should be understood, however, that althoughthese examples may describe some of the more specific details of the invention they are given primarily for purposes of illustration and the invention in its broader aspects is not limited thereto.

of a pure product are Example 1 An alcoholic solution containing &22 grams (2 mols) of diphenylguanidine was made up, and to this solution was added, 136.4 grams (1 mol) of zinc chloride, which had likewise been previously dissolved in alcohol. tions were heated slowly to evaporateloff'the alcohol and yet avoid overheating. The product obtained upon evaporation to dryness was a clear resin-like amorphous mass, which powdered up readily, and showed no hygroscopic properties. This powder softened when heated to above 84 C.

To test the utility of the diphenyl guanidinezinc chloride complex, the following samples were made up and tested. Equivalent ratios of the complex material and diphenyl guanidine alone were used in the samples.

Sample A Sample 13 Smoked rubber sheets 100 100 Zinc oxide 6 6 Sulfur H 3 3 Benzothiazyl disulfide 0. 0.75 Diphenyl guanidine 0. 445 Diphenyl guanidineZnGh combinations 0. 59

These samples were then tested in a Williams plastometer using a three minute y value in inches at C. The higher the percentage change in the y value on heating, the faster the rate of set up or premature vulcanization.

From the above table it may readily be seen The combined solu-i that diphenyl guanidine alone has a much faster rate of premature vulcanization than my new diphenyl guanidine-zinc chloride combination.

The following tests were then run to show the comparative effects of my new product and of diphenyl guanidine on the samples at full cure.

From the above tests it may be seen that the physical properties of the two samples were practically the same at fullcure.

Example 2 The amorphous di-o-tolyl guanidine-zinc chloride complex was prepared in the same manner as the diphenyl complex described in Example 1 with the mere substitution of di-o-tolyl guanidine for diphenyl guanidine. A rubber sample was then compounded containing 100 parts smoked sheets, 6 parts zinc oxide, 3 parts sulfur, 0.75 part benzothiazyl disulfide and 0.59 part of (DPG) 2ZI1C12. Tests made on this composition in the manner described in Example 1 showed that the di-o-tolyl guanidine-zinc chloride product gave an even slower rate of set-up, or premature vulcanization, than the diphenyl guanidine complex. V

What I claim is:

1. A process of preparing a complex addition compound of a diaryl guanidine and a salt of the group consisting of zinc chloride and hydrated aluminum chloride which comprises dissolving the metal chloride in alcohol, adding the diaryl guanidine thereto, heating the mixture to bring about reaction between the metal salt and the diaryl guanidine and continuing the heating until the alcohol has been substantially removed from the mass and a fused mass is obtained.

2. A process of preparing a complex addition compound of a diaryl guanidine and a salt of the group consisting of zinc chloride and hydrated aluminum chloride which comprises, dissolving the metal chloride in alcohol, adding the diaryl guanidine insolid form thereto, heating the mixture under reflux to bring about reaction between the metal salt and the diaryl guanidine, and distilling ofi the alcohol until a substantially dry and fused mass is obtained.

3. The process of claim 2, wherein the metal salt is zinc chloride. a

4. The process of claim 2, wherein the diaryl guanidineis di-o-tolyl guanidine and the metal salt is zinc chloride. a

5. The process of preparing the complex addition compounds of a diaryl guanidine and a salt of the group consisting of zinc chloride and hydrated aluminum chloride which comprises, dissolving the diaryl guanidine and the metal salt in separate quantities of alcohol, combining the resulting solutions and slowly heating the combined solutions to dryness and to fuse the residue.

6. The process of claim 5, wherein the metal salt is zinc chloride.

7. The process of claim 5, wherein the diaryl guanidineis di-o-tolyl guanidine and the metal salt is zinc chloride.

' ARNOLD R. DAVIS. 

